Induction heating device

Abstract

An induction heating device comprises a control box (2), a magnetic core (8), a movable closed yoke (7) and a plurality of temperature sensors (3, 5), wherein the magnetic core (8) is provided with at least one inductor (9, 10), the at least one inductor (9, 10) being supplied with current by a power electronic device, the power electronic device being controlled by a control circuit, the power electronic device and the control circuit being installed in the control box (2), the detachable closed yoke (7) being used to complete the magnetic circuit of the magnetic core (8), characterized in that a plurality of metal objects (4, 6) are heated simultaneously so that each metal object reaches a target temperature according to a heating cycle, and during the heating cycle, the temperature sensor monitors the temperature of the plurality of metal objects so that each metal object is connected to a temperature sensor that is not connected to any other metal object.

Description

Technical Field

[0001] The present invention relates to a device comprising an induction coil for heating a metal article such as a rolling element bearing, ring or gear by inducing eddy currents in the metal article. Background Art

[0002] EP 2728965A1 describes a known type of bearing induction heater that uses two temperature probes during heating of the bearing according to a heating cycle. One temperature probe monitors the temperature of the inner ring of the bearing and the other temperature probe monitors the temperature of the outer ring of the bearing. The difference between the two temperatures triggers a switch between a first part of the heating cycle and a second part of the heating cycle.

[0003] Generally speaking, it is known to use an induction heater with a single induction coil or with a plurality of induction coils.

[0004] There is still room for improvement. Summary of the invention

[0005] A particular object of the present invention is to provide an induction heating device for heating a metal object.

[0006] According to the present invention, the induction heating device comprises a control box and a magnetic core, wherein the magnetic core is provided with at least one inductor, and the at least one inductor is supplied with current by a power electronics device, and the power electronics device is controlled by a control circuit ( / control unit). The power electronics device and the control circuit are installed in the control box.

[0007] The device also includes a removable closing yoke and a plurality of temperature sensors, wherein the removable closing yoke is used to complete the magnetic circuit of the magnetic core.

[0008] Still according to the present invention, multiple metal objects are heated simultaneously so that the multiple metal objects all reach a target temperature according to a heating cycle, and during the heating cycle, the temperature sensor monitors the temperature of the multiple metal objects so that each metal object is connected to a temperature sensor that is not connected to any other metal object.

[0009] According to other advantageous but non-mandatory aspects of the invention, such an induction heating device may include one or more of the following features:

[0010] - the number of temperature sensors is as many as the number of different objects to be heated simultaneously;

[0011] -The magnetic core has a first arm, a second arm and a third arm, wherein the first arm, the second arm and the third arm form a core portion that is overall U-shaped or C-shaped, and the closed yoke is positioned as an open arm (open arm) across the U-shaped or C-shaped core portion to complete the magnetic circuit of the magnetic core.

[0012] - The heating device comprises a single inductor mounted on one of the arms of a U-shaped or C-shaped magnetic core.

[0013] The heating device comprises two inductors, one inductor being mounted on one of the two open arms in the U-shaped or C-shaped magnetic core, and the other inductor being mounted on the other open arm.

[0014] Another aspect of the present invention is to provide a method for heating a plurality of metal objects using the induction heating device according to the present invention, the method comprising the following steps:

[0015] a) placing a metal object around one of the arms of the core or around the closed yoke;

[0016] b) for each metal object, connecting a separate temperature sensor to each metal object;

[0017] c) setting a target temperature that each metal object will reach for each temperature sensor;

[0018] e) starting a heating cycle, for example, by a manual action comprising pressing a button;

[0019] f) Heating multiple metal objects simultaneously.

[0020] According to other advantageous but non-mandatory aspects of the invention, the method may include one or more of the following features:

[0021] - The method further comprises the following steps:

[0022] d) For each target temperature, a first temperature alarm value and a second temperature alarm value are set, wherein the first temperature alarm value is used to prevent the associated metal object from being overheated, and the second temperature alarm value is used to prevent the associated metal object from being underheated.

[0023] - During step f), at least some of the metal objects may be placed in contact with each other to facilitate heat transfer between them.

[0024] - During step c), the target temperature of all metal objects to be heated simultaneously is set to the same or different values.

[0025] Thanks to the present invention, multiple metal objects can be heated simultaneously, but they do not have to be heated at the same rate, which can be used to speed up the assembly of a system including multiple metal objects, or can be used to save time during maintenance of multiple metal objects on the same system or multiple systems located in the same area.

[0026] Thanks to the invention, a plurality of metal objects can be heated simultaneously so that they reach a desired temperature, and the desired temperatures can be different or the same.

[0027] Also, thanks to the invention, during the heating of a plurality of metal objects, a minimum number of temperature probes can be used to directly monitor the temperature of each metal object. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention and its advantages will be better understood by studying the detailed description of a particular embodiment given by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0029] - Figure 1 A first preferred embodiment of the induction heating device according to the invention is shown, wherein two metal objects to be heated are in a first relative position with respect to each other;

[0030] - Figure 2 Shows Figure 1 An induction heating device, wherein the two metal objects are in a second relative position relative to each other;

[0031] - Figure 3 A second preferred embodiment of the induction heating device according to the present invention is shown.

[0032] 1 Power supply

[0033] 2 Control box

[0034] 3.5 Temperature sensor

[0035] 4.6 Metal objects

[0036] 7 Closing yoke

[0037] 8 Magnetic core

[0038] 9.10 Inductor DETAILED DESCRIPTION

[0039] Figure 1 An induction heating device is shown, which is connected to a power supply 1 which supplies power to a control box 2 which forms part of the device ( / induction heating device). The induction heating device further comprises a magnetic core 8 on which an inductor 9 or coil 9 is provided.

[0040] Preferably, the magnetic core 8 is ferromagnetic.

[0041] The magnetic core 8 has a first arm, a second arm, a third arm and a fourth arm or closing yoke 7, the first arm, the second arm, the third arm forming an overall U-shaped or C-shaped core portion, and the fourth arm or closing yoke 7 is positioned across the open arms of the U-shaped or C-shaped core portion to complete the magnetic circuit of the magnetic core 8. The closing yoke 7 is movable or removable to allow the first metal object ( / metal object / metal product) 4 and the second metal object 6 to be arranged for heating. The inductor 9 is mounted on one of the arms of the U-shaped or C-shaped magnetic core 8.

[0042] The inductor 9 supplies current through the power electronic device controlled by the control circuit. The power electronic device ( / power electronic device) and the control circuit are installed in the control box 2.

[0043] Still according to Figure 1 The induction heating device further comprises a first temperature sensor 3 and a second temperature sensor 5. The two temperature sensors are connected to the control box 2. Preferably, the temperature sensors are each provided with a magnetic thermocouple. In addition, the first temperature sensor 3 is connected to the first metal object 4, and the second temperature sensor 5 is connected to the second metal object 6.

[0044] like Figure 1 As shown, two metal objects are positioned at a distance from each other. This is advantageous when, for example, it is desired to heat the two objects at two different temperatures.

[0045] Figure 2 Shown with Figure 1 The induction heating device is the same as the induction heating device in Figure 2 In the embodiment, the two metal objects 4, 6 are in another relative position with respect to each other. More precisely, the two metal objects are in contact with each other. This allows an efficient heat transfer between the two objects, for example from one object to the other, during the heating cycle. Advantageously, the two metal objects are in contact with each other via two surfaces that are as large as possible. Figure 2 As shown, two metal objects are in contact according to two flat side surfaces.

[0046] Advantageously, the two metal objects may be temporarily held in contact with each other during the heating cycle due to a holder (not shown).

[0047] Figure 3 A second preferred embodiment of the induction heating device is shown. For clarity, the same elements have the same Figure 1 and Figure 2 Elements of the embodiments shown in FIG. 1 are provided with the same reference numerals.

[0048] Figure 3 The second embodiment of the invention differs from the first embodiment in that it includes a second inductor 10. The first inductor 9 is mounted on one of the two open arms of the U-shaped or C-shaped magnetic core, while the second inductor 10 is mounted on the other open arm of the U-shaped or C-shaped magnetic core.

[0049] The metal objects may be rolling element bearings, rings or gears.

[0050] In an embodiment of the invention not shown, at least three metal objects are positioned around the closed yoke 7 .

[0051] In an embodiment of the invention not shown, the induction heating device comprises at least three temperature sensors.

[0052] During a heating cycle performed by the induction heating device, each metal object is connected to a temperature sensor that is not connected to any other metal object. The temperature sensor monitors the temperature of the object to which it is connected.

[0053] The metal object is heated simultaneously during the heating cycle.

[0054] In a preferred embodiment of the present invention, the induction heating device comprises as many temperature sensors as the number of metal objects to be heated simultaneously, and each temperature sensor is connected to a separate ( / unique) metal object.

[0055] In a heating cycle, multiple metal objects are heated individually until the target temperature is reached.

[0056] Preferably, the induction heating device continuously monitors temperature readings during the heating cycle.

[0057] Preferably, a first temperature alarm value is set for each temperature monitoring (target temperature) to avoid overheating of the corresponding metal object. Indeed, it has been observed that when metal objects of different sizes and / or weights are heated simultaneously, they heat at different rates and some objects reach their first alarm temperature before others.

[0058] In addition, preferably, a second temperature alarm value is set for each temperature monitoring (target temperature) to avoid underheating of the corresponding metal object.

[0059] The heating cycle for heating several metal components simultaneously is controlled by a control box.

[0060] For a given set of hardware, the heating cycle is adaptive and depends on the target value (ie, target temperature), the first temperature alarm value and the second temperature alarm value, and of course on the metal object itself (mass, volume, constituent material, etc.).

[0061] Each heating cycle consists of a number of parts which are set by the control box.

[0062] In a preferred embodiment of the invention, the heating cycle comprises a first part having a first determined duration and having a high heating rate due to a high current or multiple high currents delivered in the inductor or multiple inductors (or multiple inductors if the heating device is equipped with multiple inductors), and a second part having a second determined duration and having a lower heating rate due to a lower current or multiple lower currents delivered in the inductor multiple inductors.

[0063] In another preferred embodiment of the invention, the heating cycle comprises a third portion during which no current is delivered to the one or more inductors and for a third determined duration. This third portion may for example occur during the aforementioned first and second portions.

[0064] In another preferred embodiment of the invention, the heating cycle comprises a fourth portion during which a current or currents are passed through the one or more inductors to maintain the different metal objects at the same temperature.

[0065] Now we will describe a method for simultaneously heating a plurality of metal objects using the induction heating device according to the present invention. The method comprises the following steps:

[0066] a) Place a metal object around any of the arms of the core 8 or on the closed yoke 7. If it is desired that some or all of the metal objects reach the same target temperature, the metal objects may be positioned in contact with each other to facilitate heat transfer between the metal objects and help equalize their temperatures.

[0067] b) For each metal object, a separate ( / unique) temperature sensor is connected to each metal object, for example, by means of surface contact.

[0068] c) Set a target temperature for each metal object to reach for each temperature sensor.

[0069] d) A first temperature alarm value and a second temperature alarm value for each temperature monitoring (target temperature) are set for each temperature sensor.

[0070] Step d) is optional. In fact, in a preferred embodiment of the present invention, some values ​​are set in the memory of the control box by default. For example, the first alarm value is set to the target temperature +5°C, and the second alarm value is set to the target temperature -5°C.

[0071] Alternatively, these first temperature alarm value and second temperature alarm value may be manually set by an operator.

[0072] e) Starting a heating cycle, for example, by a manual action comprising pressing a button.

[0073] f) Heating a plurality of metal objects simultaneously. During this step, the metal objects do not have to be heated at the same rate. During this heating process, the induction heating device runs a heating cycle including one or more of the aforementioned four parts. Advantageously, the last part of the heating cycle is the aforementioned fourth part, so that the objects are respectively maintained at their desired heating temperature until the operator is ready to remove the objects.

[0074] In a preferred embodiment of the present invention, the target temperature of all metal objects to be heated simultaneously is set to the same value. In this case, an induction heating device comprising only one inductor (such as Figure 1 and Figure 2 The induction heating device in the embodiment is sufficient to heat all objects ( / products) simultaneously within a reasonable time.

[0075] In another preferred embodiment of the present invention, the target temperatures of all metal objects to be heated simultaneously are set to different values. In this case, an induction heating device including at least two inductors (such as Figure 3 induction heating device).

[0076] In another preferred embodiment of the present invention, the first temperature alarm value is set to the same value for all metal objects to be heated simultaneously.

[0077] In another preferred embodiment of the present invention, the second temperature alarm value is set to the same value for all metal objects to be heated simultaneously.

[0078] In another preferred embodiment of the present invention, the first temperature alarm value is set to different values ​​for all metal objects to be heated simultaneously.

[0079] In another preferred embodiment of the present invention, the second temperature alarm value is set to different values ​​for all metal objects to be heated simultaneously.

[0080] Thanks to the invention, several metal objects can be heated simultaneously, which can be used to speed up the assembly of a system comprising several metal objects or can be used to save time during maintenance of several metal objects on the same system or several systems located in the same area.

[0081] Thanks to the invention, a plurality of metal objects can be heated simultaneously so that they reach a desired temperature, and the desired temperatures can be different or can be the same.

[0082] Also, thanks to the invention, during the heating of a plurality of metal objects, a minimum number of temperature probes can be used to directly monitor the temperature of each metal object.

Claims

1. An induction heating device, comprising a control box (2), a magnetic core (8), a movable closed yoke (7) and a plurality of temperature sensors (3, 5), wherein the magnetic core (8) is provided with at least one inductor (9, 10), the at least one inductor (9, 10) is supplied with current by a power electronic device, the power electronic device is controlled by a control circuit, the power electronic device and the control circuit are installed in the control box (2), the movable closed yoke (7) is used to complete the magnetic circuit of the magnetic core (8), and is characterized in that: A plurality of metal objects (4, 6) are heated simultaneously so that each metal object reaches a target temperature according to a heating cycle, during which the temperature sensor monitors the temperature of the plurality of metal objects so that each metal object is connected to a temperature sensor that is not connected to any other metal object; the plurality of metal objects (4, 6) are positioned at a certain distance from each other along the movable closed yoke (7), or the plurality of metal objects (4, 6) are in contact with each other through two flat side surfaces.

2. The induction heating device according to claim 1, characterized in that: The number of temperature sensors is as many as the number of different metal objects to be heated simultaneously.

3. The induction heating device according to any one of the preceding claims, characterized in that The magnetic core (8) has a first arm, a second arm and a third arm, wherein the first arm, the second arm and the third arm form a core portion that is overall U-shaped or C-shaped, and the closed yoke (7) is positioned to span the open arm of the U-shaped or C-shaped core portion to complete the magnetic circuit of the magnetic core (8).

4. The induction heating device according to claim 3, characterized in that: The induction heating device comprises a single inductor (9) mounted on one of the arms of the U-shaped or C-shaped magnetic core (8).

5. The induction heating device according to claim 3, characterized in that: The induction heating device comprises two inductors (9, 10), one inductor (9) being mounted on one of two open arms of the U-shaped or C-shaped magnetic core, and the other inductor (10) being mounted on the other open arm.

6. A method of heating a plurality of metal objects using an induction heating device according to any one of the preceding claims, the method comprising the steps of: a) placing the metal object around one of the arms of the magnetic core (8) or around the closed yoke (7); b) for each metal object, connecting a separate temperature sensor to each metal object; c) setting a target temperature that each metal object will reach for each temperature sensor; e) starting the heating cycle; f) heating the plurality of metal objects simultaneously.

7. The method according to claim 6, characterized in that The method further comprises the following steps: d) For each target temperature, a first temperature alarm value and a second temperature alarm value are set, wherein the first temperature alarm value is used to prevent the associated metal object from being overheated, and the second temperature alarm value is used to prevent the associated metal object from being underheated.

8. The method according to claim 6 or 7, characterized in that: During step f), at least some of said metal objects are placed in contact with each other to facilitate heat transfer between them.

9. The method according to claim 6 or 7, characterized in that: During step c), the target temperature of all metal objects to be heated simultaneously is set to the same value.

10. The method according to claim 6 or 7, characterized in that: During step c), the target temperatures of all metal objects to be heated simultaneously are set to different values.

11. The method according to claim 6, characterized in that The heating cycle is started in step e) by a manual action comprising pressing a button.

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